Rolling out a ROApp - Programming GPS and OpenStreetMap Applications with Java - page 168

game rules should be reduced to a minimum, in keeping with the ROAF
paradigm, the revised game is called LondonChase or LC.
Although game rules and game sets represent programmatic constraints,
they should be kept flexible for the number of players, etc. A good way
to achieve this is by distributing them over the properties files for server,
application, and client software as predesigned in the last chapter. Obliga-
tory default values can be hard-coded in interfaces. The architect abstracts
the actual game by creating a skeleton with enough code to begin a game
and run it for a few turns.
After reading this chapter, the reader should be able to enrich the game,
or even better, create his own version of the game. With the know-how
about processing digital maps, the game can easily be transferred to any
other town.

12.2.1 Language Analysis of the Game Rules

A player, alias Mister X, is moving along a network of taxi, bus lanes, and
subway lines. The game master reveals his position (current station) every
x rounds. Additional players, called Detectives, are moving along the same
net to chase Mister X and catch him at a station. The detectives are able
to communicate with each other in order to develop a strategy to track
down Mister X. The game is \digitized" by game rounds to make initial
development easier. Every player makes one move per round in sequential
order. Mister X wins, if he is not caught before the final round is completed.
These simple rules are sucient to implement a basic game application.
Once the initial game is implemented, the reader can add items from
the original game, which uses a pool of taxi, bus, and subway tickets for
each player depending on the total number of players. The original game
board also has a boat feature for ferries on the Thames.
With every move, a player has to use one ticket according to the network
link feature used. The player can only make a particular move, if he has a
ticket for it. Naturally, this affects the strategy. Mister X has additional
options like double move and black (any feature) tickets. The detectives
get to see the tickets used in every round. Similar games, like New York
Chase have additional features like helicopters, or they allow players to
drop barriers 2 forcing other players to route around them.

12.2.2 Game Place and Time
Every ROApp should be restricted to a bounding box representing a part
of the real world. In the case of LondonChase , the box is defined as a part
of London. Initially, the game time does not have to be set to real time. In

2 Real-world barriers: wiki.openstreetmap.org/wiki/Map Features#Barrier